The full quote:

Quote Originally Posted by gbaji View Post
As to "adjusting" things in an adventure as it's going, there's nothing innately wrong with that. All GMs do it to some degree. Heck. I use the first handful of encounters specifcally to "fine tune" things. It's often very hard to tell just by looking at character sheets how the entire group will perform as a party in various situations, so I've found this to be important. Learning their strengths (and most importantly potential holes and vulnerabilities) is key to having good encounter balance in the adventure. However, any tuning or adjusting should always be made with an eye towards making the game more fun, and not in a competitive "GM vs the players" way.
Your response:

Quote Originally Posted by Devils_Advocate View Post
Quote Originally Posted by gbaji
As to "adjusting" things in an adventure as it's going, there's nothing innately wrong with that. All GMs do it to some degree. Heck. I use the first handful of encounters specifcally to "fine tune" things. It's often very hard to tell just by looking at character sheets how the entire group will perform as a party in various situations, so I've found this to be important. Learning their strengths (and most importantly potential holes and vulnerabilities) is key to having good encounter balance in the adventure.
Eh, how is that different from what ciopo's DM did to prevent him from trivializing traps? You may feel that traps aren't legitimate encounters and thus are not subject to encounter balance, but that strikes me as more of a personal bias than anything else.
Why did you trim out the one sentence in the paragraph you quoted which addressed the very question you then raised?

What ciopo's DM was doing falls squarely in the "competitive GM vs players" situation I wrote about (and not "making the game more fun"). That's how it's different.

Quote Originally Posted by Devils_Advocate View Post
Is it that "raising the DC", given that phrasing, presumably wasn't accompanied by a change in description? I can certainly agree that there's a subtle but important difference between giving an enemy raiding party better armor and giving them a +5 ScrewYouMunchkins bonus to AC.
That's part of it. But the biggest point is "why" it's being done. The GM was specifically increasing the difficulty of the traps in response to a PC having high trap detecting/disarming skills. This may seem like normal balancing of an adventure, but it has the effect of negating the character build.

There are three broad ways to make things more challenging. You can increase the number of threats, or the danger of threats, or the difficutly of threats. What's interesting is that the first two often result in positive perception by the players, while the third is often negative. If I'm really good at something (melee combat, ranged combat, spells, traps, social stuff, whatever), then the more things in the adventure that require that skill, the more I feel my character is contributing. So putting in more mooks to fight, or more things that require spells, or more traps, or more intrigue, etc is a good thing, despite that this can technically make the adventire more challenging. Same deal if we up the danger. If failure to defeat the opponents, or use the right spell, or disarm that trap, or deal with the social issue, has higher risks then that again makes the use of and value for using those things greater, which makes the players feel good about what they did (they stopped something "bigger" and "badder", right?)

But... And this is significant. If I just make the mooks tougher, or the DC/resistance to spells higher, or the traps DC higher, or the intrigue stuff harder (ie: just increasing the mechanical die roll result required to succeed), then this is negative. You aren't increasing the value of the skills or abilities of the characters, nor the rewards for using those things, but watering down the effect of them having them in the first place. If the rewards/consequences for success/failure are exactly the same, but the number I have to roll on the die to succeed is harder, then that has no effect other than to make the character less effective. That's not really "balancing" the adventure. I mean, you can approach balance that way, but IMO that's not a great way to do it, precisely because it will make the players feel like their characters are just less effecitve at eveything they do. And doing his for just one aspect of the adventure, to counter one specific characters abilities, is even worse.

Note, that increasing the difficulty while not increasing anything else is what makes this a problem. Obviously, if those increases come along with other aspects of the adventure (bigger stakes, tougher monsters, bigger rewards, etc), then that's fine. But if you're doing it just because "the PCs skills are too high, so I'll make the rolls they need to make harder" then that's "doing it wrong" IMO. In the OP case, I don't think the DM upped the rewards/stakes/whatever for overcoming these traps. He just made the die rolls needed to defeat them harder to make. So yeah, that falls squarely in "poor way to balance things".